This invention relates to building construction, and particularly to a mesh roof system for buildings, especially metal buildings with insulated roofs.
Expanded metal, metal screen, and other types of mesh have been proposed previously for use in constructing walls and ceilings of buildings. In some cases, such as in U.S. Pat. No. 4,522,004, cementitious material or plaster is applied over the mesh. Mesh has also been used to support or retain insulating material, an in U.S. Pat. No. 2,148,281.
In U.S. Pat. No. 3,506,746, a net supported by poles serves as a support for receiving plaster of the like, which hardens to form a structure in which door, windows and the like are subsequently cut. U.S. Pat. No. 545,301 describes a method of constructing an arched roof by applying concrete or cement to a corrugated wire mesh supported by structural beams.
U.S. Pat. No. 4,557,092 describes an insulating blanket having a strong scrim layer attached to its fiber barrier, to resist falling objects. It has been found difficult, however, to create joints of sufficient strength in such material to prevent heavy objects from falling through.
Finally, flexible materials have been used to support ceiling insulation in a dropped ceiling construction, as shown in U.S. Pat. No. 3,791,089.
None of the above patents adequately addresses the problem of worker safety; nor does the known prior art provide a simple, durable and attractive way of retaining glass fiber blanket insulation on the roof of a metal building. We re-address safety and structural considerations with this invention, and simultaneously provide aesthetic and functional advantages over prior roof insulation retention methods.
We are particularly concerned with construction worker safety. Unfortunately, injuries occur from time to time during roof construction, either to workmen who fall from the roof, or those below, from dropped objects. It is therefore standard and required practice to provide safety netting or other sheet material below roof installers to protect them and those below, and/or to require workers to be tied or tethered to the structure.
Dropped tools are a another problem; the safety netting designed to catch falling workmen is generally of a sufficiently large mesh (e.g., six inch mesh) to allow small tools, bolts, fasteners, and other construction materials to pass through. Conventional practice is to deploy a separate, smaller mesh debris net below the safety netting, to catch such articles.
Furthermore, required safety practices are sometimes violated. For example, if a required tether is not applied, or while it is being moved, the workman and those below him are at risk. It would be better to have a restraint that could not be avoided, and did not require a positive action to be effective. That is, a restraint analogous to an automobile air bag is preferred over one analogous to a seat belt, since the former cannot be avoided.
We have found that a very simple, attractive and durable insulated roof can be constructed with a strong mesh fabric that reduces the likelihood and severity of construction accidents resulting from falling objects, and also forms a permanent part of the roof.